The present invention is directed to a multi-chamber vacuum installation including a charge-changing chamber and a plurality of process chambers located within the charge-changing chamber. Basically, such an installation is used for heat treatment, such as in smelting and casting plants or sintering facilities, where the material to be treated is subjected to cyclical treatment under vacuum conditions.
Such known installations have two or more chambers in which significantly different conditions exist such as pressure, temperature and gas composition. In cyclical operation the material to be treated, which must pass through several processing steps, is subjected consecutively in individual chambers to the different steps. To maintain the operating conditions within the chambers over a long operating period, the material to be treated must pass through an air lock when moving from the ambient atmosphere into a chamber or vice versa.
Such air locks are expensive components. They must be equipped with at least two valves, which have to meet very high requirements. In particular, use under vacuum conditions and at high temperatures requires special design measures, as for instance suitable material selection and additional cooling systems.